Pump



United States Patent 3,516,769 ROTARY VANE HYDRAULIC MOTOR Martti Korhonen, Tasavallankatu 28, Kuopio, Finland Filed Feb. 10, 1967, Ser. No. 615,096 Int. Cl. F01c 1/00, 3/00 US. Cl. 418175 ABSTRACT OF THE DISCLOSURE A rotary vane hydraulic motor comprising an annular rotor encircling a peripheral surface on a stator and defining therewith a plurality of chambers. A plurality of radial vanes slidably disposed in vane slots in the stator project outwardly to engage the rotor. Fluid supply passages in the stator supply operating fluid to one side of each projecting vane and fluid exhaust passages in the stator communicate with the opposite sides of the pro jecting vanes respectively. A rotary sleeve valve synchronized with relative movement of the stator and rotor communicates with the bottom of each vane slot through four passages, two of which are equipped With check valves, and provides for relative rotation of the stator and rotor in either direction while supplying fluid under pressure to the bottom of each vane slot during movement of the coacting vane through an individual chamber and serving to exhaust fluid from the bottom of the vane slot as the vane moves between adjacent chambers.

The invention concerns a hydraulic motor comprising 2 Claims a stator, a rotor, and a distributing device for conducting pressure fluid into work spaces or chambers for operating fluid between the stator and the rotor and away from the workspaces or chambers. Reciprocating slide members or vanes extend radially into the workspaces.

Mechanization of transports now in progress in agriculture and forestry and endeavours to improve the economy of transports have lead to an ever increasing need for more effective ground vehicles. The same need also appears in the defense forces. The problem has been to find a suitable system of transmitting power, for instance, to the tractor trailer in order to make the wheels of the trailer also draw under difficult ground conditions. The present hydraulic motor has turned out in principle to be suitable for the purpose. At this moment there are already some such hydraulic motors which can be connected, for instance, to the hubs of the trailer wheel. The working principle of these hydraulic motors resemble that of piston engines.

This invention deals with a hydraulic motor operating according to the rotor principle, i.e. the reciprocating motion of ordinary pistons is replaced by the rotational motion of a rotor, offering a design which is simpler, more reliable in operation, cheaper and of higher efficiency. The motor has a rotating part, the rotor, e.g. the outer periphery of the device, and the stator or the stationary part fixed to the shaft. In addition the motor has a distributor of pressure fluid, obtaining its motion from the rotor, by means of which pressure fluid is conducted to the workspaces of the motor and away therefrom.

The main characterizing feature of the invention is that the workspaces consist of recesses in the peripheral surface of the rotor running parallel with the shaft of the motor, the surface of the stator, and of slide members in the stator moving in corresponding holes, at which the motion of the slide members takes place with the aid of springs and/or pressure fluid controlled by the distributing device. On reaching the switching area between the workspaces the slide member is pressed into its hole. Either the peripheral part or the control part of the motor may serve as rotor depending on which one is allowed to rotate and which one is stationary. Pressure fluid may be conducted to the workspaces either through the shaft or the outer part of the motor.

The number of workspaces is chosen according to need. In order to avoid the formation of dead centers one may for instance arrange the workspaces or the slide members unsymmetrically relative to one another, i.e. if for instance the workspaces on the periphery are of equal size the number of slide members is chosen for instance one less or one more than the number of workspaces. Different types of slide constructions, valves, etc., known as such may be used as distributors of pressure fluid.

In the hydraulic motor it is important that the turning moment immediately after bringing pressure fluid into the motor reaches maximum valve also at zero number of revolutions, i.e. for instance in the case that the vehicle has stopped the wheels of the trailer provided with hydraulic motor are made to draw at full capacity. When the terrain permits a higher speed with the vehicles own drawing power, the hydraulic motor may be switched ofl from operation, i.e. it rotates on free. By switching the flowing direction of the pressure fluid the other way around the hydraulic motor will rotate in the opposite direction, for instance on backing the vehicle. The operation of the hydraulic motor requires an outside source of power, a hydraulic pump, the control valve of which permits regulation of the above-mentioned operations. Furthermore, by regulating the flow of pressure fluid by means of the control valve stepless regulation of the rpm. of the hydraulic motor is achieved. This hydraulic motor has many applications, for instance, as means for driving conveyors, or the feeding device of circular saws, or it can be used where stepless control of the speed of rotation is required.

The invention is clarified further below with the aid of the enclosed schematical drawings, presenting only one working example of the invention, in which:

FIG. 1 presents a longitudinal section of the hydraulic motor according to the invention, and

FIG. 2 presents a cross-section of FIG. 1 along the line lIII,

. FIG. 3 presents on a larger scale the slide member, including related parts partly visible,

FIG. 4 presents a longitudinal section of the rotary slide used as distributor of pressure fluid,

FIG. 5 presents different stages of operation of the rotary slide according to FIG. 4,

FIG. 6 presents the bores of the distributor of pressure fluid in motor shaft and stator, and

FIG. 7 presents the distributor bores in the rotary slide.

In the hydraulic motor according to the drawing the shaft does not rotate but only the outer periphery, and pressure fluid is conducted to the motor through the shaft.

In the drawing the symbols designate the following: 0 switching area, 1 rotor, 2 slide member or vane, 3 stator, 4 shaft, 5 rotary slide, 6 end Wall, 7 end wall, 8 bearing, 9 flange, 10 packing, 11 ring packing, 12 shaft nut, 13 one-way valve, 14 ring packing, 15 workspace, 16 pressure fluid inlet channel, 17 pressure fluid return channel, 18 waste fluid discharge channel, 19 pressure fluid inlet channel, 20 fluid discharge channel.

According to the drawing the stator 3 is fixed by means of wedges 21 to the stationary shaft 4 to which the circular rotor 1 is mounted by means of bearings 8 to rotate about the stator 3. The inner peripheral surface of the rotor 1 is provided at intervals in the axial direction with recesses 15, for instance the bottom of which are concentric with the rotor shaft, which recesses together with the D. A. SCHNACKE June 23, 1970 PUMP 4 Sheets-Sheet 5 Filed July 25, 1968 DONALD A. SCHNACKE INVENTOR. 'J M ATTORNEYS June 23, 1970 D. A. SCHNACKE 3,516,770

' PUMP Filed July 25, 1968 4 Sheets-Sheet 4 8 DONALD AQSCHNACKE INVENTOR.

WIMMIW ATTORNEYS United States Patent US. Cl. 418240 6 Claims ABSTRACT OF THE DISCLOSURE A pump which includes a stator mounted in a housing with an annular chamber formed therebetween and the stator is provided with a plurality of angularly spaced blade slots which extend completely through the stator from a bore therein to the annular chamber and blades are positioned in these slots and at their inner ends are adapted to make sealing engagement with the surface of a rotor which is adapted to rotate in the bore. Inlet port means are provided on one side of each of the blades and outlet port means are provided on the opposite side of each of the blades. Pressurized fluid normally leaks between a blade and the blade slot from the outlet port means to the annular chamber so that pressurized fluid is contained in the annular chamber. A conduit or other opening is provided in the stator which extends from the annular chamber to the clearance between the blade and the blade slot on the inlet port means side of the blade.

Prior art devices of this type have the inherent difficulty of the rotating rotor, in engaging the blades, having a tendency to exert a tipping force on the blade caused extreme wear on the stator next adjacent the blade slot at the place where the blade slot connects with the bore within which the rotor resides. In addition to causing extreme wear and frequent replacement of parts by this action, it has also been found that it is diflicult to obtain relatively high pressures with the pump. For the sake of example, with a prior art pump of this general construction it was possible to obtain pressurized fluid at approximately 1000 p.s.i. with relatively severe wear as explained above, and with the provision of porting the pressure fluid from the annular chamber to the inlet port means side of the blades it has been possible to develop approximately twice as much pressure, or on the order of 2000 psi. In addition to this, the ported fluid pressure from the annular chamber has the effect of exerting a force against the blades which tends to keep the blade straight in its slot in its reciprocating movement, resulting in little or no wear and has the effect of keeping the blade square with the surface of the rotor thereby producing a better seal with resultant higher pressures.

FIG. 1 is a side elevational view in section of a pump constructed in accordance with the teachings of the present invention;

FIG. 2 is a view taken generally along the line 2-2 of FIG. 1;

FIG. 3 is a view taken generally along the line 33 of FIG. 1;

FIG. 4 is a view taken generally along the line 44 of.

Patented June 23, 1970 ice ly by the reference numeral 20 and as shown in the drawin-g, includes in combination a housing 22 and the housing is provided with wall means 24 which serve to define a bore in the housing. A stator member 26 is mounted in the bore 24 and as viewed in FIG. 1 has a right end portion which is of a slightly smaller diameter than the bore 24 so as to define an annular chamber 28 between the outer diameter thereof and the diameter of the bore. The left end of the stator member 26 is of a diameter to precisely fit the bore at this particular position and this part of the stator is provided with an annular groove 31 which communicates with a fluid inlet 33 in the housing. A cover 35 is secured by screws to the right end of the stator member 26 and the cover 35 is provided with a central opening 36 and is also provided with two outlet ports 39 and 40, respectively. A housing cover 42 closes the right end of the housing 22 and is secured in position by means of bolts 44. The housing cover is provided with. a central opening 43 to provide for the exit of pressurized fluid from the pump 20.

The stator member 26 is provided with an internal bore 47 which is adapted to receive a rotor 49 which is provided with three lobes, each identified by the reference numeral 50. The rotor has a right end 51 which is rotatably received in the central opening of the cover 35 and the rotor shaft 52 exits the stator member 26 through a central opening in the left side thereof as viewed in FIG. 1. First and second blade slots 54 and 55, respectively, are provided in the stator member and these blade slots extend in a generally radial direction and completely through the stator member from the internal bore 47 to the annular chamber 28. First and second blades 58 and 59 are located in the blade slots 54 and 55, respectively, and at their inner ends it will be noted they serve to engage the rotor 49 as it goes through its rotative movement. FIG. 9 shows the blade 58. The stator is provided with an annular groove 62 which extends around the outer circumference thereof and within this groove is provided a spring member 64 in the nature of a circumferentially extending piece of wire which extends slightly greater than (see FIG. 3) so as to be in engagement with the outer portion of each of the blades 58 and 59, to constantly urge these blades into engagament with the outer surface of the rotor 49.

First and second inlet ports 66 and 67 are provided in the stator and open into the bore of the stator member on what will be referred to as a first rotative side of each of the blades 58 and 59. First and second outlet or pressure ports 70 and 71 also are provided in the stator member and open into the internal bore of the stator member on a second rotative side of the first and second blades 58 and 59, respectively. As viewed in FIG. 3, the rotation of the rotor is in a clockwise direction and as will be appreciated by those skilled in the art, the lobes on the rotor pick up fluid from the inlet ports 66 and 67 and in traveling toward the outlet ports 70 and 71, serve to pressurize the fluid and eject the pressurized fluid through the outlet ports 70 and 71.

In view of the nature of construction of pumps made in accordance with the present teachings, there is a leakage in the clearance between the blades and the blade slot with which it resides, from the outlet port to the annular chamber 28 along surface 74.

As mentioned hereinabove, the rotation of the rotor acting against the blade has a tendency to cause a tipping action of the blade within its slot which causes extreme wear adjacent the blade slot at the bore of the stator member and on the inlet port side. This area is indicated at 79. This extreme wear requires frequent replacement of the parts and undesirably short life for the stator member. In addition, this tipping action contributes to the inability to obtain as good a seal as desired between the end of the blade and the surface of the rotor.

In accordance with the present disclosure, first and second opening 76 and 77 have been drilled through the stator member 26 and these openings extend from the annular chamber 28 and intersect the blade slots 54 and 55 at a position which is preferably closer to the bore of the stator member than to the annular chamber and on the inlet port side of the blades. This permits pressurized fluid to pass from the annular chamber to exert a straightening or stabilizing force on the blades which is in opposition to the tipping or bending action created by the rotation of the rotor.

FIG. 8 demonstrates a slight variation in the construction shown in FIGS. 6 and 7 in that a passage 80 has been provided in the stator member to interconnect the inner ends of openings 76 and 77 so as to insure the presence of fluid pressure along substantially the entire length of the blades as distinguished from two localized areas. The passage 80 is shown extending from opening 76 to the right edge of 26 because of manufacturing methods employed to produce passage 80. FIGS. 6 and 8 have omitted the blades therefrom for more clarity and in FIG. 8 the same numerals are used as in FIG. 6.

As a result of this invention, it has been possible to double the pressures attainable by the pump and the extreme wear which has resulted in the corner 79 of the stator member between the blade slots and the inlet means has practically been eliminated. Increased efiiciency results because of a more free movement of the blade in its slot because of the film delivered from the annular chambers as Well as the force exerted on the blades which tends to keep them straight in the slots.

Although this invention has been described in its preferred form with a certain degree of particularity, it is understood that the present disclosure of the preferred form has been made only by way of example and that numerous changes in the details of construction and the combination and arrangement of parts may be resorted to without departing from the spirit and the scope of the invention as hereinafter claimed.

What is claimed is:

1. A pump including in combination a housing, wall means defiining a bore in said housing, a stator member mounted in said bore and being of a slightly smaller diameter than said bore to define an annular chamber With said bore, said stator member having an internal bore to receive a rotor and having at least first and second oppositely disposed and generally radially extending blade slots extending through said stator member from said internal bore to said annular chamber, a rotor mounted for rotation in said internal bore of said stator member and having a plurality of lobes for pressurizing fluid, first and second blades located in said first and second blade slots and at their inner ends engaging said rotor, means urging said blades into engagement with said rotor, first and secinlet ports in said stator member opening into said internal bore thereof on a first rotative side of said first and second blades, first and second outlet ports in said stator member opening into said internal bore thereof on a second rotative side of said first and second blades, rotation of said rotor being in such a direction as to cause fluid to be moved by said lobes from said inlet ports toward said outlet ports and pressurized and ejected from said outlet ports, pressurized fluid at said outlet ports leaking to said annular chamber along the clearance between said blade slots and said blades on said second rotative side of said blades, and wall means defining at least one opening extending from said annular chamber only through said stator member and terminating at each of said blade slots only on said first rotative side of said blades which transmits fluid pressure against said blades on only one side thereof to prevent tipping of said blades.

2. A pump as claimed in claim 1 wherein said wall means which defines said at least one opening comprises two spaced openings each of which transmits fluid pressure against each blade at two areas.

3. A pump as claimed in claim 2 wherein a passage connects the inner ends of each of said two spaced openings along said blade slots.

4. A pump which includes the provision of a housing within which is mounted a stator and between the two an annular chamber is formed, the stator is provided with a radial blade slot which extends from an internal bore therein to the annular chamber and a blade is located therein which engages a rotatable, lobed rotor mounted in the internal bore and inlet means conducts fluid to one side of the blade in the internal bore and outlet means conducts pressurized fluid from the internal bore from the other side of the blade, the improvement which comprises providing an an opening leading from the annular chamber to the blade slot only on the inlet means side of the blade so as to exert a force on only said inlet means side of the blade tending to keep the blade straight in the blade slot against the tipping action on the blade caused by the engagement of the rotating rotor therewith.

5. A pump as claimed in claim 4 wherein at least two, spaced openings are provided which lead from the an nular chamber through the stator to the blade slot.

6. A pump as claimed in claim 5 wherein a passage connects the inner ends of said two spaced openings and extends along and opens into the blade slot.

References Cited UNITED STATES PATENTS 2,492,678 12/1949 Dall 103123 2,583,633 1/1952 Cronin 123-14 3,194,122 7/1965 Kee 91-104 DONLEY I. STOCKING, Primary Examiner W. I. GOODLIN, Assistant Examiner 

